Abstract

The system which was studied in the present work consisted of one liquid undergoing vaporization by contact with a hotter immiscible liquid. The liquids and vapor were contacted in a counterflow spray column with only differential increases in vapor quality. Experiments yielded vertical temperature profiles, flow rates of the phases, liquid holdups, pressure drops, and a characterization of flow patterns. A micro-computer was utilized for measuring temperatures in the column at the rate of 1500 to 1600 times per second at several depths. Analysis of the experimental data indicate that the maximum temperature difference between the phases is 0.5F/sup 0/, and that a temperature crossover occurs at the lower end of the column. The heat transfer fluid undergoes flash vaporization at its inlet at the top of the column, and much of its sensible heat is tranferred to the dispersed phase near the top of the column. Temperature profiles along the length of the boiler are nearly flat, and very little heat transfer occurs in the lower part of the boiler. A chemical method was developed for measuring effective interfacial area in a direct contact boiler. The theoretical basis of the method is discussed, and physico-chemical data necessary for applicationmore » of the technique are reported. Water solubility of methyl salicylate was measured as a function of temperature, and the second order reaction rate coefficient for saponification of methyl salicylate by sodium hydroxide was determined from sodium hydroxide concentration versus time data and a computer model of a well-mixed semibatch reactor. The activation energy for the reaction was found to be 9.58 kilocalories per gram mole.« less

@article{osti_6223376,
title = {Experimental investigation of direct contact three phase boiling heat transfer},
author = {Bruce, W.D.},
abstractNote = {The system which was studied in the present work consisted of one liquid undergoing vaporization by contact with a hotter immiscible liquid. The liquids and vapor were contacted in a counterflow spray column with only differential increases in vapor quality. Experiments yielded vertical temperature profiles, flow rates of the phases, liquid holdups, pressure drops, and a characterization of flow patterns. A micro-computer was utilized for measuring temperatures in the column at the rate of 1500 to 1600 times per second at several depths. Analysis of the experimental data indicate that the maximum temperature difference between the phases is 0.5F/sup 0/, and that a temperature crossover occurs at the lower end of the column. The heat transfer fluid undergoes flash vaporization at its inlet at the top of the column, and much of its sensible heat is tranferred to the dispersed phase near the top of the column. Temperature profiles along the length of the boiler are nearly flat, and very little heat transfer occurs in the lower part of the boiler. A chemical method was developed for measuring effective interfacial area in a direct contact boiler. The theoretical basis of the method is discussed, and physico-chemical data necessary for application of the technique are reported. Water solubility of methyl salicylate was measured as a function of temperature, and the second order reaction rate coefficient for saponification of methyl salicylate by sodium hydroxide was determined from sodium hydroxide concentration versus time data and a computer model of a well-mixed semibatch reactor. The activation energy for the reaction was found to be 9.58 kilocalories per gram mole.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Thu Jan 01 00:00:00 EST 1981},
month = {Thu Jan 01 00:00:00 EST 1981}
}

An experimental and analytical investigation of convective film boiling was performed. The experimental work involved the acquisition of the axial variation of thermodynamic nonequilibrium in convective film boiling. The experiment resulted in the reporting of 579 data points for thermodynamic nonequilibrium, much larger than the size of the entire nonequilibrium data base at the start of this study. Comparison of existing convective film boiling models to these new data, as well as some data taken at Idaho National Engineering Laboratory in conjunction with this study, showed that no previously existing correlation could adequately predict the data. The high vapor generationmore » rate near the quench front was an unexpected finding from the vapor superheat data, and no previously existing model could predict this behavior. Therefore, a two-region vapor generation model was developed consisting of a near-field region and a far-field region. The heat transfer from the well to the vapor is also higher than can be calculated by a vapor-phase correlation, which has been commonly used in existing models. The improvement in heat transfer coefficient was correlated in terms of a sink function which represents the enhancement of heat transfer due to the entrained liquid. A two-dimensional conservation equation approach was formulated to evaluate the radial and axial variation of the vapor superheat.« less

A mathematical model of stratified turbulent liquid/turbulent gas flow has been developed and put in the form of a design procedure for predicting pressure drop, holdup, and gas and liquid phase heat transfer coefficients. The model was tested against air-water data taken in a 63.5 mm I.D. tube. The experimental apparatus constructed is a marked improvement over previous systems used in similar studies. Experiments were extended into the annular regime and a tentative design procedure proposed for predicting heat transfer coefficients to the liquid film.

The nucleate boiling heat-transfer coefficient and the maximum heat flux were studied experimentally as functions of velocity, quality and heater diameter for single-phase flow, and two-phase flow of Freon-113 (trichlorotrifluorethane). Results show: (1) peak heat flux: over 300 measured peak heat flux data from two 0.875-in. and four 0.625-in.-diameter heaters indicated that: (a) for pool boiling, single-phase and two-phase forced convection boiling the only parameter (among hysteresis, rate of power increase, aging, presence and proximity of unheated rods) that has a statistically significant effect on the peak heat flux is the velocity. (b) In the velocity range (0 < U/submore » infinity/ < 0.68 ft/sec) covered in this study the peak heat flux appears to exhibit a shallow minimum in the vicinity of U/sub infinity/ - 0.4 ft/sec. (c) The two-phase flow peak heat flux is 8 to 15% higher than the single-phase flow peak heat flux and the increase is independent of the quality of the flowing mixture. (d) For simultaneously heated elements at identical power inputs the excursion into film boiling always occurs at the most upstream heater regardless of the flow conditions. (2) Boiling pattern: single-phase forced convection drastically reduces the thickness of the two-phase zone surrounding the heater. (3) Local surface temperature: the coldest and the hottest spots of the heater are identified as the bottom (0/sup 0/ position or the point of impact of the incident fluid) and the top (180/sup 0/ position) of the test element, respectively.« less

Thesis submitted to Univ. of Washington, Seattle. The process design of a prototype facility for carrying out a test program on solidifying liquid radioactive wastes is presented. The test program is divided into two phases. During the initial phase of the test program approximately two million gallons of non-boiling wastes, that is low heat generating wastes, from the Purex process are to be processed through the prototype facility for determining the effect of different operating variables on the behavior of the in-tank wastes, particulate entrainment in the evolved vapor, the rate of concentration, and the waste concentration factor. Upon completionmore » of the first phase of the test program, the prototype facility is to be installed in an adjacent waste storage tank to check out the portability of the facility and to determine the feasibility for concentration of a blended waste containing various amounts of heat generating fission products. In addition to the storage benefits gained by concentrating these wastes, information obtained from operating the prototype facility is to be used for designing production scale units capable of concentrating other stored and currently accumulating wastes. (auth)« less